Manchuria is a historical name given to a large geographic region in northeast Asia. Depending on the definition of its extent, Manchuria usually falls entirely within the People’s Republic of China, or is sometimes divided between China and Russia. The region is commonly referred to as Northeast China (simplified Chinese: 东北; traditional Chinese: 東北; pinyin: Dōngběi). This region is the traditional homeland of the Xianbei, Khitan, and Jurchen peoples, who built several states historically. The region is also the home of the Manchus, after whom Manchuria is named.
Manchuria was the homeland of several nomadic tribes, including the Manchu, Ulchs and Hezhen. Various ethnic groups and their respective kingdoms, including the Sushen, Donghu, Xianbei, Wuhuan, Mohe, Khitan and Jurchens have risen to power in Manchuria. At various times in this time period, Han Dynasty, Cao Wei Dynasty, Western Jin Dynasty, Tang Dynasty and some other minor kingdoms of China established control in parts of Manchuria and in some cases tributary relations with peoples in the area. Various kingdoms in Korea, such as Gojoseon, Buyeo, Goguryeo and Balhae were also established in parts of this area. With the Song Dynasty to the south, the Khitan people of Western Manchuria created the Liao Empire in the region, which went on to control adjacent parts of Northern China as well.
In the early 12th century the Tungusic Jurchen people, who were Liao’s tributaries, overthrew the Liao and formed the Jin Dynasty (1115–1234), which went on to control parts of Northern China and Mongolia. During the Yuan Dynasty (1271–1368), Manchuria was administered under the Liaoyang province. In 1375, Nahacu, a Mongol official of the Northern Yuan in Liaoyang province invaded Liaodong, but later surrendered to the Ming Dynasty in 1387. In order to protect the northern border areas the Ming decided to «pacify» the Jurchens in order to deal with its problems with Yuan remnants along its northern border. The Ming solidified control over Manchuria under Yongle Emperor (1402–1424). Starting in the 1580s, a Jianzhou Jurchen chieftain, Nurhaci (1558–1626), started to unify Jurchen tribes of the region. Over the next several decades, the Jurchen took control over most of Manchuria. In 1616, Nurhaci founded the Later Jin Dynasty.
In 1644, after the Ming Dynasty’s capital of Beijing was sacked by the peasant rebels, the Jurchens (now called Manchus) allied with Ming general Wu Sangui and seized control of Beijing, overthrowing the short-lived Shun Dynasty and establishing Qing Dynasty rule (1644–1912) over all of China. But in 1858, a weakening Qing Empire was forced to cede Manchuria north of the Amur to Russia under the Treaty of Aigun. In 1860, at the Treaty of Peking, the Russians managed to obtain a further large slice of Manchuria, east of the Ussuri River. As a result, Manchuria was divided into a Russian half known as «Outer Manchuria», and a remaining Chinese half known as «Inner Manchuria». In modern literature, «Manchuria» usually refers to Inner (Chinese) Manchuria. As a result of the Treaties of Aigun and Peking, China lost access to the Sea of Japan.
Inner Manchuria also came under strong Russian influence with the building of the Chinese Eastern Railway through Harbin to Vladivostok. In the Chuang Guandong movement, many Han farmers, mostly from the Shandong peninsula moved there. Japan replaced Russian influence in the southern half of Inner Manchuria as a result of the Russo-Japanese War in 1904–1905. Most of the southern branch of the Chinese Eastern Railway was transferred from Russia to Japan, and became the South Manchurian Railway. Japanese influence extended into Outer Manchuria in the wake of the Russian Revolution of 1917, but Outer Manchuria had reverted to Soviet control by 1925. Manchuria was an important region for its rich mineral and coal reserves, and its soil is perfect for soy and barley production. For pre–World War II Japan, Manchuria was an essential source of raw materials. Without occupying Manchuria, the Japanese probably could not have carried out their plan for conquest over Southeast Asia or taken the risk to attack Pearl Harbor on the 7th of December, 1941.
Around the time of World War I, Zhang Zuolin established himself as a powerful warlord with influence over most of Manchuria. During his rule, the Manchurian economy grew tremendously, backed by immigration of Chinese from other parts of China. The Japanese assassinated him on June 2, 1928, in what is known as the Huanggutun Incident. Following the Mukden Incident in 1931 and the subsequent Japanese invasion of Manchuria, the Japanese declared Inner Manchuria an «independent state», and appointed the deposed Qing Xuantong Emperor (Puyi) as Emperor of Manchukuo. Under Japanese control Manchuria was one of the most brutally run regions in the world, with a systematic campaign of terror and intimidation against the local Russian and Chinese populations including arrests, organised riots and other forms of subjugation. Manchukuo was used as a base to invade the rest of China.
After the atomic bombing of Hiroshima, Japan in 1945, the Soviet Union invaded from Soviet Outer Manchuria as part of its declaration of war against Japan. Soon afterwards, the Chinese communists and nationalists started fighting for the control over Manchuria. The communists won in the Liaoshen Campaign and took complete control over Manchuria. With the encouragement of the Soviet Union, Manchuria was then used as a staging ground during the Chinese Civil War for the Communist Party of China, which emerged victorious in 1949. Ambiguities in the treaties that ceded Outer Manchuria to Russia led to dispute over the political status of several islands. This led to armed conflict in 1969, called the Sino-Soviet border conflict. In 2004, Russia agreed to transfer Yinlong Island and one half of Heixiazi Island to the PRC, ending an enduring border dispute.